Traditionally, the economic analysis of a project has been
undertaken last in a series of studies covering the technical,
institutionalorganizational- managerial, social, commercial-marketing and
financial aspects (Gittinger, 1982). For the tsetse and trypanosomiasis problem,
this approach has recently been formalized with the development of SITE analysis
(Doran and Van den Bossche, 2000); SITE is a process for screening strategy
options by the four criteria on which the acronym is based:

Socio-economic

Institutional

Technical

Environmental.

The various options for intervention are then scored and
ranked according to these criteria, and conflicts between the results for the
different criteria explored. The remit of this paper obviously falls within the
socio-economic component. There are a variety of techniques for analysing the
economics of interventions in the field of agriculture and livestock production,
which have been summarized in the animal health context by Rushton, Thornton and
Otte (1999), the possible approaches are also discussed, with specific reference
to parasitic diseases of livestock, in Perry and Randolph (1999). The technique
that has been most used in the past, and which is favoured by many of the
authors in Perry (1999) is some form of social benefit - cost analysis. This can
be underpinned as appropriate by the use of a herd model simulating output from
the livestock population with the project being implemented and consequently
with improved production parameters, and comparing this to the situation in the
absence of the project. Integrating epidemiological with economic models is also
very helpful, particularly for a vector-borne disease such as trypanosomiasis
(see McDermott and Coleman, 2001). Perry and Randolph (1999) emphasize the need
to:

integrate
the products of good epidemiological studies into economic
frameworks;

integrate techniques for
economic analysis and simulation models of animal production and health dynamics
within a systems framework.

Published textbooks on the evaluation of animal health
programmes, such as Putt et al. (1987) and Dijkhuizen and Morris (1997)
also support this approach. It remains the most practical tool for analysing and
ranking projects according to the relationship between their costs and their
expected impact.

At this stage it is appropriate briefly to review some of the
main techniques used in benefit - cost analysis which are particularly relevant
in the field of tsetse and trypanosomiasis control. The main steps in benefit -
cost analysis are:

quantifying the
expected benefits of an intervention over time;

quantifying the expected costs
of an intervention over time;

comparing these, coming up
with a standard measure (net present value, benefit - cost ratio or internal
rate of return) that makes it possible to

- assess the interventions
profitability

- compare it, or rank it against other possible interventions
with which it is competing for funds or which are alternatives for development
in the same production sector;

undertaking sensitivity
analyses to examine how sensitive the result is to changes in key assumptions,
such as the effectiveness of the disease-control measures, the rate of adoption
of an animal health intervention or the growth of human and livestock
populations in the project area.

Social benefit - cost analysis studies the effect of an
intervention, usually described as a project, on society as a whole, so it takes
into account all the benefits and all the costs, regardless of who spends the
money or to whom the benefits accrue. In the tsetse and trypanosomiasis field
the benefits tend mostly to accrue to livestock and crop farmers, while the
expenditures are usually shared between donors, government and local farmers.
While many analyses focus on the total social costs and benefits, increasingly,
studies are looking at the effect of interventions from the financial viewpoint
of the livestock keepers. Thus, the studies by Woudyalew et al. (1999)
and Blanc, Le Gall and Cuisance (1995) calculate benefit - cost ratios from the
farmers point of view. New ways of modelling benefits at farm level are
also being developed (McDermott, Coleman and Randolph, 2003).

Time value of money

A key principle underlying the benefit - cost approach is
assigning a lower weighting to future income/expenditure as against current
income/expenditure[1]. The rationale for this can
be presented in a number of ways.

Using money has an
opportunity cost, which banks acknowledge by paying interest to customers
for using their money, and charging it when customers borrow the banks
money; in the public sector this opportunity cost exists because projects are
competing for scarce public funds and allocating money to one project within a
sector usually takes it away from an alternative use.

In this case, we should select
projects which provide a good return on money invested, as measured by
the compound interest which the benefits add to the costs over time.

Finally, society places a
relative valuation on present as against future income; this is the social
time preference rate. This rate tends to be high in poor societies where
current needs are urgent, and lower in wealthy societies where the future is
more secure.

In benefit - cost analysis this relative weighting of present
as against future income (the implied interest rate or minimum acceptable return
on money invested) is undertaken by using a process called discounting. This
process is not just applied in commercial business ventures, but is an integral
part of the project analysis process in public sector projects in all areas (see
Gittinger, 1982 on agricultural project analysis; Drummond et al., 1997
for human health projects; Putt et al., 1987; Dijkhuizen and Morris,
1997; Rushton, Thornton and Otte, 1999 for animal health projects and discussion
in Kristjanson et al., 1999). Discount rates used in agricultural and
livestock analysis generally range from 8 percent to 15 percent, and in the
field of human health they range from 3 percent to 5 percent (Acharya and
Murray, 1997). With the exception of Budd (1999), whose objective was to present
the global magnitudes involved rather than undertake an analysis over time, the
economic studies of the trypanosomiasis problem cited above, have applied
discount rates of 8 percent or over in their analyses. Since the use of discount
rates penalizes future benefits as against present costs, the use of high
discount rates has been debated in projects that are expected to have very
long-term benefits or many intangible benefits that are difficult to
quantify, in particular in the field of the eradication of infectious diseases
in humans (Acharya and Murray, 1997). The authors conclude that it can sometimes
be argued that the selection of human diseases for eradication should be
undertaken without discounting using other, very stringent, criteria, and that a
proportion of global health funding be set aside for this purpose. Nevertheless,
costs should be discounted in order to select the most cost-effective options.
However, other writers, even in the field of human health, conclude
technically and theoretically there are good reasons for discounting
benefits as well (as costs) and discounting health benefits has been
advocated as good economic practice in all guidelines on economic
evaluation (Glydmark and Alban, 1997).

As a consequence, it is recommended here that, when dealing
with a disease which:

mainly affects
livestock and agricultural production, and

occurs in a continent where
there are huge and urgent alternative demands on finance,

we maintain the convention of using discount rates. In view of
the inclusion of tsetse elimination, which would have very long-term benefits,
among the options for dealing with trypanosomiasis, the discount rate used in
the analysis below was 5 percent rather than the 10 percent which would more
usually be applied in the livestock sector.

Discounting has important implications in comparing control
and eradication options. This is particularly so in the field of tsetse control
where some techniques, such as targets or ground spraying, can be used for
either control or eradication. Furthermore, eradicated areas may need to be
treated repeatedly because of re-invasion or failure to completely eliminate a
tsetse population.

Figure 1 illustrates some of the implications that discounting
has for decision-making on options for tsetse and trypanosomiasis control. In
this figure, annually recurring expenditures over 20 years are compared to
once-off expenditures incurred at the start of a 20- year period. The example
used is of expenditures on trypanocides, which are costed at US$1.50 a dose, and
then multiplied by the number of cattle per km2, in order to obtain
an annual total cost per km2 at different cattle population
densities. The once-off expenditures could equally well refer to annual
recurrent expenditure on tsetse control, for example using pour-ons.

The figures on the y-axis show what the equivalent
amount spent per km2 at the beginning of the period would be. Thus,
at about 20 cattle per km2, an annual expenditure of US$6, or four
doses of trypanocide, would be equivalent to an initial outlay on tsetse
elimination of US$1 500 per km2. If tsetse elimination cost less than
this, it would be the more attractive option, however if it cost more, a very
clear argument would need to be presented to show that it was economically
justified. Obviously this model simplifies the situation, for example:

it does not take
into account the fact that the cattle population might be increasing during the
period;

it only looks at
cost-effectiveness, implying that the two options have equivalent benefits over
time, whereas tsetse clearance may be subject to re-invasion, annual control
usually does not totally remove the effects of disease, drug resistance can
gradually appear;

it is based on a 20-year time
horizon;

it assumes that tsetse
clearance is a once-off expenditure occurring in year one of the project,
whereas it may take several years to achieve and be followed by some ongoing
annual costs, for example the cost of barriers.

FIGURE 1Comparing annual to once-off
expenditure

Note: Calculated over 20 years at a 5% discount rate

All of these factors could easily be taken into account in a
comprehensive benefit - cost analysis, in particular the changes in cattle
populations can be tackled using a herd model as outlined below.

Despite these limitations, the analysis is useful in
illustrating the basic nature of some of the decisions which have to be made in
the field of tsetse and trypanosomiasis control. Similar graphs could be
constructed to show:

the annual benefit
per head of cattle which would be needed in order to justify a certain initial
outlay on tsetse clearance - again using Figure 1, it implies that if the
benefit is expected to be of the order of US$6 per year, the average cattle
population per km2 would have to be about 12.5 in order to justify a
once-off expenditure of US$1 000 on tsetse clearance;

the level of annual
expenditure on tsetse suppression for which it would be more economic, if
feasible, to switch to tsetse clearance - for example, if suppression costs
US$30 per km2, this would be equivalent to a once-off expenditure of
just under US$400 per km2; if suppression were deemed to be only 50
percent as effective in controlling the disease as permanent clearance, this
figure could be adjusted to just under US$800 (400/0.5).

Threshold values

In economics, as in other disciplines, it is often useful for
the decision-maker to be able to define threshold values or cut-off points,
above which a certain decision is appropriate and below which another becomes
valid. In economic and financial decision-making these are often referred to as
break-even points. They define the point at which a project breaks
even, meaning that above this point the benefits exceed the costs; below
this point the costs exceed the benefits. In the same way that the cut-off point
for a diagnostic test can be adjusted to make it either more specific or more
sensitive, in economics, the cut-off discount rate chosen can make it possible
to give different weights to long-term benefits as against current costs. Also,
as in other disciplines, the threshold value has to be interpreted by the
decision-maker, and may often consist of a range of values within which it is
felt that the result is doubtful. In project appraisal, these
doubtful projects, are those which should be put at the bottom
of the pile and only looked at when no better alternatives are found or
when circumstances change, such as their score on another of the SITE
criteria.

The threshold concept is particularly helpful in assessing the
economic viability of different tsetse and trypanosomiasis control schemes. Some
of the thresholds are:

cattle population
density at the start of a programme (as seen in Figure 1 this determines benefit
levels and cost levels for per head of cattle control methods such
as trypanocides and pourons);

human population density at
the start of the programme (influencing fly habitat and also helping determine
benefit units, for example the potential for using draught power);

for each area the cost of
once-off tsetse clearance plus the ongoing cost of barriers, weighted by the
risk of needing to retreat the area;

the cost of the technically
feasible ongoing tsetse suppression techniques.

These thresholds can be defined with some accuracy for a
particular area or region with similar areas - but as everyone who has worked on
the tsetse and trypanosomiasis problem knows, generalizing is very difficult.
There are other criteria to be included, in particular human and livestock
population pressure in neighbouring areas. It should be noted at this stage that
on the benefit side these thresholds are, to all intents and purposes, the same
ones that are used in the GIS filtering process in order to identify promising
areas for intervention (e.g. Gilbert et al., 2001; Hendrickx, 2001;
Hendrickx et al., 1999; PAAT, in prep.).

To complete this filtering process, benefit - cost analysis
adds the possibility of summarizing much of this information in a single
measure. The most practical for the purposes of this analysis is the benefit -
cost ratio (BCR),[2] which is expressed
as:

Benefit-cost ratios have the added advantage that they can
easily be adjusted from the above measure, which calculates the return on all
monies invested, to measures that analyse the return to different groups such as
farmers, livestock keepers or to investment, research, etc.

The following sections discuss how the information above can
be treated to produce realistic and consistent estimates on the impact of the
disease over time and in response to various interventions.

Partial analysis - defining the
with and without scenarios

The basic tool used in farm management in order to quantify
the costs and benefits of a proposed modification to the production system is
partial analysis, which is also sometimes called partial budgeting. It provides
a useful framework for categorizing benefits and costs, and when the framework
is completed it acts as a checklist, which applies particularly well to
disease-control interventions (e.g. Putt et al, 1987; Dijkhuizen and
Morris, 1997; Rushton, Thornton and Otte, 1999).

For trypanosomiasis the main items to be included under the
four headings that comprise the partial analysis framework are shown in Table
1.

With and without project scenarios
for benefits

Determining what the with and without
project scenarios are is always difficult. On the benefits side, in terms of
livestock productivity, it depends on studying before and after, or with disease
and without disease situations, and should thus follow the same principles as an
intervention trial in epidemiology. Swallow (PAAT, 2000), in his review paper,
discusses the basis on which the production parameters with and without the
disease were estimated in the various studies, distinguishing between the
following approaches:

longitudinal
monitoring of herds, comparing parameters for individuals detected parasitaemic
and those not detected parasitaemic;

monitoring the health and
productivity of cattle herds in similar areas distinguished by different levels
of trypanosomiasis risk or challenge;

monitoring livestock before
and after control measures were undertaken.

TABLE 1Partial analysis for tsetse and trypanosomiasis
interventions

Costs

Benefits

a) Extra costs

c) Extra revenue

Extra cost of implementing the proposed
intervention:

chemo-prophylaxis

use of pour-ons

traps and targets

ground-spraying, SAT, SIT,
other forms of vector control.

Extra costs associated with an increase in livestock
production (more animals) and productivity.

Output from herd with intervention in place minus
output from herd without intervention (output to include herd
growth, animal traction and if possible a value for manure as well as milk and
meat).

b) Revenue foregone

d) Costs saved

Negative side-effects of the chosen control strategy on land
use, environment, and development of drug resistance (these are mostly difficult
to quantify). Loss or reduction in a particular category of output, e.g. lowered
rural meat consumption due to a reduction in emergency slaughter following from
improved herd health.

Saving in trypanocide costs due to implementation of vector
control options. Saving in cost of curative trypanocides if a successful
preventive trypanocide regime is established.

Total costs

Total benefits

An analysis of these studies and discussion of the parameters
obtained is outside the scope of this paper, however it will be important (see
Chapter 5) to consider these issues when making recommendations on how to
standardize the collection of data required for the economic analyses.

The importance of correctly assessing the with and
without scenarios can be illustrated by following the series of
graphs given in Figure 2. Taking the size of the cattle population as an
indicator of benefit levels, Figure 2a shows the null hypothesis
situation, i.e. that the cattle population would remain unchanged in the absence
of interventions to control the tsetse and trypanosomiasis problem. This
no change scenario is often unconsciously adopted in evaluations,
forgetting that while the population growth rate might remain more or
less the same for some years in the absence of interventions, the population
itself is unlikely to be static.

FIGURE 2Alternative with and
without intervention scenarios for tsetse and trypanosomiasis
control

Figure 2b illustrates the situation where interventions to
control the disease yield the highest profits - where a population is declining
in the absence of control, owing to the severity of the disease - but would
increase if effective control measures were implemented. This was the case, for
example, in the Yalé area of Burkina Faso (Kamuanga et al., 2001a)
where there had been massive losses due to the disease, reflected in a huge
decline in the population.

Figure 2c, however, illustrates a situation that is often
encountered in West Africas moist savannah zone, where even in the absence
of interventions to control tsetse and trypanosomiasis, the cattle herds are
still growing. This has been the situation in Côte dIvoire, due
perhaps to farmers use of trypanocides and to the presence of
trypanotolerant cattle (Camus, 1981; Shaw, 1993; Pokou, Swallow and Kamuanga,
1998). A similar situation is found in parts of northern Nigeria (Shaw, 1986).
In this situation, potential benefits are lower than under the previous
scenarios.

Finally, Figure 2d can be seen as an extension of Figure 2c,
showing what the situation would be if there were a production ceiling, usually
imposed by an areas livestock carrying capacity limit, itself determined
both by the quality of the natural forage and by the proportion of land taken up
for farming. In this case, production under the with and
without scenarios converges and the effect of disease control is to
enable production from cattle to reach its ceiling earlier on. Benefits under
this scenario, although lower than under the others, may still be
significant.

An issue which further complicates assessments of the impact
of tsetse control strategies, is the possibility of using pour-on preparations
that also affect ticks, and thus produce a wider range of benefits whose impact
is difficult to compare to those of other tsetse and trypanosomiasis control
strategies.

This discussion has not directly mentioned the issue of cattle
migration, and more specifically immigration into areas that have been cleared
of tsetse. A method for dealing with this issue, which seems to work well, is to
take the cattle population affected by the project as being:

those animals
present in the area at the start of the project,

plus any animals that migrate
into the area during the course of the evaluation period,

and assume that both groups benefit from improved
productivity, since the immigrants presumably moved into the area because they
hoped for better conditions - whether better grazing or less risk from disease.
This approach produces realistic results for actual situations and can be
integrated into a herd model (Putt et al., 1989; Shaw, 1990,
1993).

With and without project scenarios
for costs

Identifying the with project costs is usually
relatively straightforward, since these mainly involve direct expenditure on a
new disease-control programme. However, if one of the impacts of the project is
to increase livestock numbers and/or productivity, this may involve extra
production costs for livestock keepers and these need to be included in the
extra costs.

More difficult to assess are the without project
costs. The main issue to consider here is how are farmers now, and how
will they continue to manage the problem of trypanosomiasis in the future?
More evidence of how they do this is slowly accumulating. CIRDES, ILRI and ITC
(2000) comment on farmers expertise in integrated disease
management and state The strategies that livestock owners adopt for
production under trypanosomiasis risk have elements that take effect over the
long-term, medium-term and short-term. Choices with long-term effects,
especially regarding livestock breed and type, condition choices with
medium-term effects, especially regarding transhumance and use of acaricides for
tsetse and tick control. Similarly, choices with long-term and medium-term
effects condition choices with short-term effects, especially the use of
trypanocidal drugs. Looking at the RTTCP countries, Van den Bossche and
Vale (2000) discuss the widespread use of trypanocides, and state that
preference is given to the treatment of oxen and cows, i.e. the productive
animals in the herd and Doran (2000) points out that in the surveys
conducted, trypanosomiasis challenge seems to affect calving rates, but not
cattle mortality rates which may be masked by the effects of curative treatment.
This tendency to prioritize on cows and oxen is very sound in economic terms.
Looking at the economics of traditional cattle-production systems in West
Africa, most of the output by value either consists of milk and draught power or
is linked to herd growth. These in turn are a function of the health of adult
females and draught oxen. Thus, taking a herd model and simulating the results
of removing the effects of the disease in these two groups of animals deals with
around 75 percent of the losses due to trypanosomiasis in many
situations.

TABLE 2Partial analysis for tsetse control in an area
where farmers currently use trypanocides

Costs

Benefits

a) Extra costs

c) Extra revenue

Cost of the tsetse control strategy implemented. Extra costs
for rearing more animals.

Output from herd under tsetse control minus output from that
herd if the current use of trypanocides had continued.

b) Revenue foregone

d) Costs saved

As noted in Table 1, but difficult to quantify.

Saving in trypanocide costs due to implementation of vector
control options. Reduced risk of drug resistance.

Total costs

Total benefits

Thus, taking into account with and
without project scenarios in this way means that the relevant
partial analysis framework for the introduction of tsetse control would be as
given in Table 2.

In Table 2, the benefits under c) would be the added increase
in output due to a switch from using drugs to tsetse control and under d) for
the savings that livestock keepers would now be able to make on trypanocides. In
this context, Pokou, Swallow and Kamuanga (1998) and CIRDES, ILRI and ITC (2000)
did note that farmers in northern Côte dIvoire continued to use
drugs in the tsetse suppression area, probably partly because they were not
completely aware of the extent to which tsetse control has reduced risk, and
partly because some isk was actually still present and animals were being sent
outside the tsetse control area on seasonal transhumance. Other factors might be
the usefulness of these drugs against babesiosis, and the fact that in many
places, trypanocides are still among the few veterinary drugs which are widely
available.

Other methodological
issues

There are a number of other methodological issues in project
analysis, which have relevance to the analysis of the tsetse and trypanosomiasis
problem.

The distinction between financial and economic analyses should
briefly be mentioned (see Gittinger, 1982 for a detailed discussion). This
operates at two levels.

a) The viewpoint from which the analysis is made -
an economic analysis usually embraces the benefits and costs to society as a
whole, while a financial analysis tends more often to be undertaken looking at
the costs and benefits to individuals, specific groups or organizations (e.g.
crop farmers, livestock keepers, cattle traders, governments).

b) The prices used in the analysis - there is a convention of
using accounting or shadow prices which attempt to
adjust market prices so that they better reflect real resource costs; this is
particularly the case for some prices such as foreign exchange rates, or
agricultural prices that are fixed by government, accounting prices have been
used in looking at tsetse and trypanosomiasis control economics, for example by
Jahnke (1974) and Itty (1992).

In practice, many economists end up producing a sort of
halfway house midway between an economic analysis and a financial
analysis, by making adjustments for over-valued exchange rates and taxes and
subsidies while leaving most other prices at their current market values. The
term economic tends to be used as the general term covering both
approaches, and this convention is followed here. Most of the analyses conducted
here are economic in the sense that they look at the benefits and costs to
society rather than individual groupings, and financial in the sense that they
are based on current market prices. However, as discussed at the start of
Chapter 3, a number of studies have looked at the benefits and costs from the
financial viewpoint of farmers and livestock keepers (Blanc, Le Gall and
Cuisance, 1995; Woudyalew et al., 1999; McDermott, Coleman and Randolph,
2003). In addition, a number of studies have examined farmers willingness
to pay for tsetse control, these were studied for a West African situation by
Kamuanga et al. (2001b) and the various studies were reviewed by Kamuanga
in PAAT (2003).

Dealing with risk and uncertainty is obviously crucial when
looking at the possible outcomes and costs of tsetse and trypanosomiasis
control. Sensitivity analyses are an effective way to deal with this, by
studying the effects of changes in key assumptions and seeing how sensitive the
projects performance is to likely changes. As mentioned above, identifying
the threshold at which a project becomes profitable, through some form of
break-even analysis is another way of defining the projects limits (e.g.
with respect to disease incidence in the absence of control or minimum human and
cattle populations necessary to generate sufficient benefits to make the project
economically feasible).

The time horizon selected is also important, especially when
comparing control and eradication options, as mentioned above in the section on
Time value of money, page 11. The figure conventionally selected in
benefit - cost analyses is 20 years and this has been used in the model runs
below. Sensitivity analyses looking at 30 and 40 years are desirable,
particularly if eradication is being considered - however, these need to be very
carefully interpreted, since looking that far ahead into the future involves
considerable speculation, and the assumption that current trends will continue
can be enormously misleading.

Defining the project to be
analysed

Finally, against the background of discussions on huge
area-wide programmes to eliminate the fly over large sections of the continent,
what is the rationale for trying to prioritize and select intervention
programmes to control the tsetse and trypanosomiasis problem? The terms of
reference for this paper were to produce guidelines for prioritizing
intervention programmes on the basis of economic criteria. In economics,
decisions are made at the margin, that is by comparing the potential additional
benefit from a proposed change to the likely additional costs as shown in the
framework for partial analysis (see Tables 1 and 2). In looking at the tsetse
and trypanosomiasis problem, it is essential that individual projects are
defined, analysed and ranked using each of the SITE criteria (see beginning of
Chapter 3). The size of such projects should take into account the
following.

The project must
be technically feasible - the area must have a defined trypanosomiasis problem,
be of a suitable size for the most cost-effective control technique (such as a
fourth-level river basin for area-wide tsetse eradication, see Hendrickx, 2001;
PAAT, in prep.) or the zone should be covered by a defined group capable of
concerted action (such as farmers with a particular problem and outlook, a
development project or an administrative or extension structure).

Funding for the project must
exist - there is no point in analysing a project for which funds will run out
half way through, since this will prejudice the outcome and render the initial
appraisal invalid.

The technical capacity to
carry out the project must exist.

Thus, it is strongly argued that each individual project, of
whatever size, needs to be assessed on its own merits, not, especially at this
stage, for its contribution to a continent-wide super-programme. The issue of
timing, in particular, is important here. It is recognized that, as stated by
the PAAT Advisory Group at its 8th meeting in 2002, while we resolve to
reduce and ultimately eliminate the constraint of tsetse-transmitted
trypanosomiasis in man and animals ... progress towards the final objective is
best achieved through concerted efforts towards intervention in a sequential
fashion, with the focus on those areas where the disease impact is most severe
and where control provides the greatest benefits to human health, well-being and
sustainable agriculture and rural development. It follows that undertaking
tsetse eradication work on the fringes of the tsetse distribution, where the
tsetse habitat is already marginal, cannot be justified purely in order to
accrue benefits which will only start very far in the future and in another part
of the continent. However, as Chapter 4 shows, it is in some of these fringe
areas in West Africa, that controlling trypanosomiasis in cattle does yield high
benefits.

[1] This weighting is
completely independent of inflation accounting, and applies to sums of money
calculated at constant prices; readers should be aware of a common tendency to
confuse the two processes.[2] The two other standard
measures can be used for ranking projects in this field but have some drawbacks:
the Net Present Value (NPV) reflects project size as well as profitability and
the Internal Rate of Return (IRR) has mathematical limitations which mean that,
in particular, control using trypanocides can easily produce exaggerated IRRs of
over 300 percent.